job: Reduced metadata keys.
job: Reduced metadata keys.

  * Do not store anymore compiler info at the job level.

Change-Id: I56154046ee8e320cd1915757cabc222fadcb6787

joyxu/kernelci-backend,kernelci/kernelci-backend,kernelci/kernelci-backend,joyxu/kernelci-backend,joyxu/kernelci-backend